Polynesians With a Purpose

Thursday, June 01, 1995

More than three millennia ago, the people we now call Polynesians sailed in canoes from islands in Southeast Asia to Tonga and Samoa in western Polynesia, and from there to the Cook Islands, Tahiti, Hawaii, and Easter Island. But by the time Europeans arrived in Polynesia 300 years ago, such epic voyages were the subject of myths. Western Polynesian societies were quite different, culturally and linguistically, from eastern islands. Anthropologists have assumed that these differences arose from some 3,000 years of isolation and that the long ocean voyages ended for unknown reasons shortly after the far-flung islands were settled. But Patrick Kirch, an anthropologist at the University of California at Berkeley, and Marshall Weisler, an anthropologist at the University of Otago in New Zealand, have found evidence of continued contact among distant islands as recently as a thousand years ago.

Kirch and Weisler traced trade items, particularly stone tools found on the islands. Many early Polynesian tools were made of basalt, the bedrock of the islands themselves. But conventional methods of analyzing stone, which examine the crystal structure of thin slices to identify the stone’s provenance, are not fine enough to discriminate among basalt types. So researchers had been unable to make use of the majority of artifacts found at Polynesian sites--until Weisler hit upon the idea of using energy-dispersive X-ray fluorescence to analyze basalt. In that technique, a sample of stone is bombarded with X-rays until its electrons become excited and produce their own, secondary X-rays. These are characteristic of the elements in the sample, allowing researchers to determine its composition.

Weisler found that the ratios of certain elements--say, zirconium to strontium--were unique to basalts from a particular island. He showed that 3,000- to 1,600-year-old basalt adzes that Kirch found on Ofu, one of the Manua Islands, came from Tutuila, about 60 miles away. He also found that 1,000-year-old adzes from Mangaia came from Tutuila as well--nearly 1,000 miles distant.

Findings like that confirm that the Polynesian voyagers did more than just settle their islands by chance, perhaps after having been blown hundreds of miles off course. The older view is that islands were quickly settled, colonized just once, and then isolation set in, says Kirch. But these new results show that there was continued contact between these societies much later than what was thought to be the case. The Polynesians have oral traditions of two-way voyages, but a lot of this had been at times dismissed as being mere myth. Now we’re finally able to get some sort of objective scientific handle on these myths.